The 2009 Lions tourist was integral in Wales' resurgence to defend their Championship crown.
He reckons the achievement was bigger than last season's Grand Slam and has urged Wales to build on their success.
"The title was one to savour because of the way we turned it around," said Phillips.
"Was Saturday better than the Grand Slam games? I think it probably was because so many things just could not have gone any better.
"But rugby is a cut-throat industry. Everyone loves us now, but the players know the score. We know that if we don't carry this on, move on to bigger and better things, the critics will come for us.
"I was really happy with my game throughout the Six Nations, I thought the team went on to perform brilliantly and it was probably the best time I have ever had with the team.
"But you don't just stop there.
"We have not been that far away from beating Australia in the last 18 months and that is still the next step for us...to keep the focus and start beating them, New Zealand and South Africa," he admitted.
"Those sides have great depth of talent and, yes, they are still a level up from us and we must aspire to them.
"There's nothing wrong saying that. We can be proud of what we've done in the Six Nations, but the fact is we have not taken the next step of beating them.
"If we keep our focus and carry on the way we are going, we can start to do that."
But before that Phillips is likely to pull on another red jersey Down Under.
The former Scarlets, Cardiff Blues and Ospreys star was the Lions' Test scrum-half four years ago in South Africa and he admits it would be an honour to go on back-to-back tours
"It's only around the corner now, and I'd be lying if I said I wasn't thinking about it," added Phillips.
"What can I say? I hope to go, it would be a massive honour. All I can do is keep my fingers crossed in the coming weeks."